Direct Self-Control Strategy for Axial Flux Ironless Permanent Magnet Synchronous Motors Based on Duty Ratio Control

Axial Flux Ironless permanent magnetic synchronous motor (AFIPMSM) is a new permanent magnetic motor. It has many advantages, such as high torque-to-weight ratio, good efficiency, no cogging torque, and the sinusoidal back EMF. It gradually becomes the good choice in drive system. However, the small armature winding inductance causes the current is not continued with the PWM control based on VSI, it is a fatal shortcoming of the motor on the control. To solve this problem, a novel automatic control method based on a modified dc-dc converter is used to regulate the current. And the torque control rule is proposed to ensure the tracking of the torque-producing current of the AFIPMSM to the commanded value according to the motor rotor position under all operating conditions. Simulation and experimental results confirm the validity of the proposed control method. Direct Self-Control Strategy for Axial Flux Ironless Permanent Magnet Synchronous Motors Based on Duty Ratio Control